The present invention relates to glass forming and transport mechanisms, and in particular to glass forming and transport mechanisms to shape curved glass, such as, for example, glass in vehicles.
Glass components used in automobiles, such as windshields, are often complex shaped parts. During the shaping process, hot glass enters a vacuum mold and is shaped close to its final shape. The glass needs to be brought into the mold at a predetermined angle on a hot ring in order to allow for proper shaping. The mold drops down and picks up the glass off of the hot ring via vacuum pressure. The hot ring is removed, and then a cold ring is brought under the glass, with the glass released onto the cold ring from the mold. The glass is then picked up by a hood via a vacuum pressure. The hood has teeth that are adjustable and, since the glass is still hot, can shape the glass slightly. So, if the hood is mis-adjusted, the glass can be mis-shaped. The hood transports the glass over the top of cooling conveyor pads on a shuttle (a cooling conveyer with fans for cooling the glass). Since it is glass, and so somewhat brittle, the glass must be at the proper angle when dropped onto the pads of the shuttle or it has a greater tendency to chip or crack. For particularly complex shaped glass, such as vehicle windshields with complex curvature, assuring the proper angle can be difficult, especially since, for the complex shaped glass, this angle can be different than that needed in the mold. The orientation of the glass during the shaping process, then, is typically driven by the need for a proper orientation of the glass as it is placed on a cooling shuttle from a hood. If the placement of the glass on the cooling shuttle does not allow for the glass to contact all of the shuttle pads essentially at the same time, the glass will have a tendency to chip and crack. Since conventionally, the tilt of the hood is fixed, the glass tilt relative to the shuttle pads cannot be adjusted while the hood is moving the glass from the cold ring to the shuttle. Because of this, the orientation of the glass as it is brought into the vacuum mold would not be optimum.
In order to assure the proper angle at the time of dropping the glass onto the shuttle pads, then, and assuring optimum orientation of the glass in the vacuum mold, the glass forming process requires the use of an articulated hot ring tool when forming the complex shapes. An articulated hot ring has hinges on a pair of opposite sides (for a windshield, this is typically the driver and passenger sides). But articulated hot rings are generally not desirable if a non-articulated hot ring can be employed instead. By employing a non-articulated hot ring instead of an articulated hot ring, the cycle time for forming the glass can be reduced, there is less scrap because there won't be any hinge kinks, as can happen with articulated tooling, as well as a reduction in glass chips, which can occur when an air suspension block drops the glass onto the hinges of the articulated hot ring. Further, the tooling will require less maintenance because of the reduced number of moving components.
Thus, it is desirable to have a glass forming system and process that overcomes the drawbacks of the prior systems, which require an articulated hot ring in order to form complex shaped glass parts and have the glass at the optimum orientation when dropped onto the pads of the cooling conveyer.